Winter Care of the Broodmare

Follow these tips and help support cold weather horse health.

From AQHA Corporate Partner Zoetis

Keeping mares healthy throughout pregnancy is important for the delivery of healthy, happy foals. For owners of American Quarter Horse mares waiting for the spring foaling season, it’s crucial to remember to take extra care of them during the cold winter months.

In winter, pregnant mares need to maintain healthy nutrients in their diets and sustain their body condition. They won’t have the benefit of lush grass to supplement their diets, so ensuring that they have a supply of quality hay can help them maintain optimal body condition. You might need to adjust the amount of grain they receive if they cannot maintain an adequate body condition on a diet of hay.

Your veterinarian can help determine what body condition your mare is in. Keep in mind that pregnant mares will need extra feed during the last trimester.1

Also, make sure they have enough clean water. Horses will consume more water if it is kept around 45 degrees F. If this is not feasible in your barn, make sure that any ice formed is removed at least twice daily.

One important part of caring for your horse during winter is making sure she has enough hay. Download AQHA's FREE How to Tie a Haynet report to help you safely provide it for her.

Additionally, be sure to follow recommended vaccination schedules. The American Association of Equine Practitioners (AAEP) recommends that core and risk-based vaccines be given to breeding mares at four to six weeks prior to foaling.2 All broodmares should be vaccinated against tetanus, eastern and western equine encephalomyelitis (EEE and WEE), West Nile and rabies.

Most pregnant mares are also vaccinated against equine influenza and equine herpesvirus Type 1 (EHV-1).  In the fifth, seventh and ninth months of gestation - generally fall and winter, depending on when you’ve bred - mares need a rhinopneumonitis (EHV-1) vaccine, as the disease can cause pregnant mares to abort. In fact, pregnant mares have a more than four times greater risk of abortion due to EHV-1 when not vaccinated compared with mares vaccinated for protection against EHV-1.3-8

To help prevent abortions, consider giving an equine rhinopneumonitis vaccine such as PNEUMABORT-K® + 1b.  Other vaccinations can minimize the threat of strangles, rotavirus and Potomac horse fever. Your veterinarian also can advise you on which vaccinations are likely to be beneficial in your situation and suggest when to administer them.

Finally, it is essential for good health during the winter to keep your mares comfortable and their body temperatures regulated. If your horses have been body clipped or exposed to freezing rain, sleet or snow, consider putting dry blankets on them to help them stay dry and warm.

Make sure your horse gets plenty of hay this winter. Learn how to properly tie up her haynet with AQHA's FREE How to Tie a Haynet report.

The winter months also can be a good time to prepare the foaling stall. Make certain there aren’t any sharp objects or hazards that could harm the foal or its mother. Inventory first aid supplies to use with foaling.

Overall, as long as pregnant mares are getting enough to eat, receive proper nutrition, are vaccinated against diseases and are kept warm, they can generally fare well during winter. Using a routine schedule can make it easier to maintain each mare throughout the year. Work with your veterinarian to create a year-round wellness program that incorporates parasite control, vaccinations, dental exams, nutritional guidance and barn biosecurity. This will help keep your broodmares in peak condition, no matter the weather.

For more information on PNEUMABORT-K+1b, contact your veterinarian or visit Learn more about other Zoetis equine products at

1 Cleary Lake Veterinary Hospital. Preparing your broodmares for the winter. 2012. Available at: Accessed September 5, 2015.
2 American Association of Equine Practitioners. Vaccinations for Adult Horses. Available at: Accessed September 5, 2015.
3 Bryans JT, Allen GP. Application of a chemically inactivated, adjuvanted vaccine to control abortigenic infection of mares by equine Herpesvirus 1. Dev Biol Stand 1982;52:493-498.
4 Tengelsen LA, Yamini B, Mullaney TP, et al. A 12-year retrospective study of equine abortion in Michigan. J Vet Diagn Invest 1997;9:303-306.
5 United States Department of Agriculture. Equine 2005, Part I: Baseline Reference of Equine Health and Management. Available at: Accessed September 5, 2015.
6 Giles RC, Donahue JM, Hong CB, et al. Causes of abortion, stillbirth, and perinatal death in horses: 3,527 cases. 1986-1991. J Am Vet Med Assoc 1993;203(8):1170-1175.
7 Hong CB,  Donahue JM, Giles RC, et al. Equine abortion and stillbirth in central Kentucky during 1988 and 1989 foaling seasons. J Vet Diagn Invest 1993;5(4):560-566.
8 University of Kentucky, College of Agriculture. Equine Disease Quarterly: Equine Herpes Virus Abortions. July 2008. Available at: Accessed September 5, 2014.
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